BG8.16 Krsna guarantee

 Bhagavad Gita — Chapter 8, Verse 16

Sanskrit (8.16):
आब्रह्मभुवनाल्लोकाः पुनरावर्तिनोऽर्जुन ।
मामुपेत्य तु कौन्तेय पुनर्जन्म न विद्यते ॥

Transliteration:
ābrahma-bhuvanāl lokāḥ punarāvartino ’rjuna
mām upetya tu kaunteya punar janma na vidyate

Translation (simple):
“O Arjuna, all worlds—from the highest realm of Brahma downwards—are subject to repeated birth and death. But one who attains Me never takes birth again.”

Key idea:
Even reaching the highest heavenly realms (like that of Brahma) doesn’t free a soul permanently from the cycle of rebirth (samsara). True liberation (moksha) comes only by realizing or attaining the Divine (Krishna).

Meaning in plain terms:
No matter how high you go in existence—power, heaven, status—it’s still temporary. Only spiritual realization leads to a final end of the cycle.

If you want, I can also give  a deeper philosophical explanation or  commentary from different traditions (like Advaita, Bhakti, etc.).